Uniqueness and regularity for the Navier-Stokes-Cahn-Hilliard system

TL;DR

This paper investigates the mathematical properties of the Navier-Stokes-Cahn-Hilliard system, establishing uniqueness and regularity of solutions in two and three dimensions, which advances understanding of fluid interface dynamics.

Contribution

It provides new results on the uniqueness and regularity of solutions for the coupled Navier-Stokes and Cahn-Hilliard system in bounded domains.

Findings

Uniqueness of weak solutions in 2D.

Existence and uniqueness of global strong solutions in 2D.

Local strong solutions in 3D with initial velocity conditions.

Abstract

The motion of two contiguous incompressible and viscous fluids is described within the diffuse interface theory by the so-called Model H. The system consists of the Navier-Stokes equations, which are coupled with the Cahn-Hilliard equation associated to the Ginzburg-Landau free energy with physically relevant logarithmic potential. This model is studied in bounded smooth domain in R^d, d=2 and d=3, and is supplemented with a no-slip condition for the velocity, homogeneous Neumann boundary conditions for the order parameter and the chemical potential, and suitable initial conditions. We study uniqueness and regularity of weak and strong solutions. In a two-dimensional domain, we show the uniqueness of weak solutions and the existence and uniqueness of global strong solutions originating from an initial velocity u_0 in V, namely u_0 in H_0^1 such that div u_0=0. In addition, we prove further regularity properties and the validity of the instantaneous separation property. In a three-dimensional domain, we show the existence and uniqueness of local strong solutions with initial velocity u_0 in V.